ORs of developing RA (overall), ACPA-positive RA and ACPA-negative RA for subjects worked in the cold, in cold outdoor and cold indoor environment
| RA (overall) | ACPA-positive RA | ACPA-negative RA | ||||
| Exposure status | Cases/controls | OR (95% CI) | Cases/controls | OR (95% CI) | Cases/controls | OR (95% CI) |
| Unexposed | 2783/4815 | 1.0 (ref.) | 1811/4815 | 1.0 (ref.) | 972/4815 | 1.0 (ref.) |
| Cold* | ||||||
| Ever | 853/1023 | 1.5 (1.4 to 1.7) | 574/1023 | 1.6 (1.4 to 1.8) | 279/1023 | 1.4 (1.2 to 1.6) |
| Current | 354/392 | 1.6 (1.4 to 1.9) | 236/392 | 1.7 (1.4 to 2.0) | 118/392 | 1.5 (1.2 to 1.9) |
| Past | 499/631 | 1.4 (1.3 to 1.7) | 338/631 | 1.5 (1.3 to 1.8) | 161/631 | 1.3 (1.0 to 1.5) |
| Cold outdoor† | ||||||
| Ever | 658/805 | 1.5 (1.3 to 1.7) | 435/805 | 1.5 (1.3 to 1.7) | 223/805 | 1.4 (1.1 to 1.6) |
| Current | 289/339 | 1.5 (1.3 to 1.8) | 188/339 | 1.5 (1.2 to 1.8) | 101/339 | 1.5 (1.2 to 1.9) |
| Past | 369/466 | 1.4 (1.2 to 1.7) | 247/466 | 1.5 (1.3 to 1.8) | 122/466 | 1.3 (1.0 to 1.6) |
| Cold indoor† | ||||||
| Ever | 175/177 | 1.7 (1.4 to 2.1) | 125/177 | 1.9 (1.5 to 2.4) | 50/177 | 1.4 (1.0 to 1.9) |
| Current | 60/47 | 2.3 (1.6 to 3.4) | 46/47 | 2.8 (1.8 to 4.2) | 14/47 | 1.5 (0.8 to 2.8) |
| Past | 115/130 | 1.5 (1.2 to 2.0) | 79/130 | 1.6 (1.2 to 2.1) | 36/130 | 1.4 (0.9 to 2.0) |
*Missing information on 23 (0.6%) cases and 87 (1.5%) controls.
† Missing information on 43 (1.2%) cases and 128 (2.2%) controls.
ACPA, anticitrullinated protein antibody; RA, rheumatoid arthritis.
OR adjusted for age (10 strata) sex, residential area and recruitment time period (1996–2006 and 2006–2014).